Polyphenols complexes were extracted from Common millet (CM), Long-grain rice (LGR) and Huaihe wheat (HW), purification method, components and functional characteristics were studied. Higher phenol content (18.7 in CM, 12.9 in LGR and 22.3 mg g −1 in HW) was obtained by the high-speed shear, with high antioxidants (DPPH 89.2% in HW, ABTS 81.6% in LGR, FRAP 0.83 in HW) after purified. Thirteen typical polyphenol complexes were identified from 21 peaks by UHPLC-LTQ-Orbitrap-MS/MS. Gingerenone A was first detected in CM, HW and LGR; (+/−)-Gingerol was first detected in CM and HW. Morphology by TEM displayed a rough spherical structure with 200-500 nm. Peculiarly contained hydroxyl polyphenol (5-(3,4-Dihydroxyphenyl) valeric acid, Apigenin-8-C-xylosyl-6-C-glucoside), polyphenols with B-rings (Trans-cinnamic acid, Gingerenone A) and the highest contents (+/−)-Gingerol with hydroxyl and Sinapinic acid with B-rings, CM had a higher α-amylase inhibition rate (80.5%) than LGR and HW, which providing a foundation for the development of hypoglycaemic drugs.